1. Field of the Invention 
The present invention relates to a lock, and more particularly to a lock with a sliding block movably received in the control knob such that the pivotal movement of the control knob is able to drive the latch to move accordingly. 
2. Description of Related Art 
When referring to a lock with a pivotal control knob and a latch driven by the pivotal movement of the control knob, normally, the latch is firmly mounted on the control knob so that when the control knob is pivoted, the latch is driven to rotate in a direction the same as that of the control knob. When the latch is rotated, the latch is able to connect/disconnect to a locking bar which is firmly mounted on a surface to switch between a locking/unlocking status. In general, a wide variety of different elements may be involved to firmly mount the latch on the control knob, which complicates the structure of the lock and hence the manufacture cost is high. Furthermore, the user will need to use the key all the time to switch between locking and unlocking status, which is quite troublesome. 
To overcome the shortcomings, the present invention tends to provide an improved lock to mitigate and obviate the aforementioned problems. 